X28C256

5 Volt, Byte Alterable E

PROM

Characteristics subject to change without notice

3855-2.0 8/19/98 T3/C0/D0 RZ

DESCRIPTION

The X28C256 is an 32K x 8 E

PROM, fabricated with

Xicor's proprietary, high performance, floating gate
CMOS technology. Like all Xicor programmable non-
volatile memories the X28C256 is a 5V only device. The
X28C256 features the JEDEC approved pinout for byte-
wide memories, compatible with industry standard RAMs.

The X28C256 supports a 64-byte page write operation,
effectively providing a 78

s/byte write cycle and en-

abling the entire memory to be typically written in less
than 2.5 seconds. The X28C256 also features

DATA

and Toggle Bit Polling, a system software support
scheme used to indicate the early completion of a write
cycle. In addition, the X28C256 includes a user-optional
software data protection mode that further enhances
Xicor's hardware write protect capability.

Xicor E

PROMs are designed and tested for applica-

tions requiring extended endurance. Inherent data re-
tention is greater than 100 years.

FEATURES

Access Time: 150ns

Simple Byte and Page Write
-- Single 5V Supply

--No External High Voltages or V

Control

Circuits

-- Self-Timed

--No Erase Before Write
--No Complex Programming Algorithms
--No Overerase Problem

Low Power CMOS:
--Active: 60mA
--Standby: 200

Software Data Protection
-- Protects Data Against System Level

Inadvertent Writes

High Speed Page Write Capability

Highly Reliable Direct Write

Cell

-- Endurance: 100,000 Write Cycles
-- Data Retention: 100 Years

Early End of Write Detection
--

DATA

Polling

--Toggle Bit Polling

256K

X28C256

32K x 8 Bit

PIN CONFIGURATION

A14

A12

A7
A6
A5
A4
A3
A2
A1
A0

I/O0
I/O1
I/O2

VSS

VCC
WE

A13
A8
A9
A11
OE

A10
CE

I/O7
I/O6
I/O5
I/04
I/O3

X28C256

PLASTIC DIP

CERDIP

FLAT PACK

SOIC

3855 FHD F02

TSOP

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

X28C256

A3
A4
A5
A6
A7
A12
A14
NC
VCC
NC
WE
A13
A8
A9
A11
OE

32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17

A2
A1
A0

I/O0
I/O1
I/O2

VSS

I/O3
I/O4
I/O5
I/O6
I/O7

A10

3855 ILL F23

A6
A5
A4
A3
A2
A1
A0

I/O0

A8
A9
A11
NC

A10
CE

I/O7
I/O6

1 32 31 30

14 15 16 17 18 19 20

X28C256

I/O

LCC

PLCC

3855 FHD F03

X28C256

PIN DESCRIPTIONS

Addresses (A

)

The Address inputs select an 8-bit memory location
during a read or write operation.

Chip Enable (

)

The Chip Enable input must be LOW to enable all read/
write operations. When

is HIGH, power consumption

is reduced.

Output Enable (

)

The Output Enable input controls the data output buffers
and is used to initiate read operations.

Data In/Data Out (I/O

I/O

)

Data is written to or read from the X28C256 through the
I/O pins.

Write Enable (

)

The Write Enable input controls the writing of data to the
X28C256.

PIN NAMES

Symbol

Description

Address Inputs

I/O

Data Input/Output

Write Enable

Chip Enable

Output Enable

+5V

Ground

No Connect

3855 PGM T01

3855 FHD F01

X BUFFERS

LATCHES AND

DECODER

I/O BUFFERS

AND LATCHES

Y BUFFERS

LATCHES AND

DECODER

CONTROL

LOGIC AND

TIMING

256K-BIT
E2PROM

ARRAY

I/O0I/O7

DATA INPUTS/OUTPUTS

VCC

VSS

A0A14

ADDRESS

INPUTS

FUNCTIONAL DIAGRAM

X28C256

I/O0

VSS

A12

VCC

I/O1

I/O2

I/O3

A14

I/O4

I/O5

I/O7

A10

A11

I/O6

A13

BOTTOM VIEW

PGA

3855 FHD F04

PIN CONFIGURATION

X28C256

DEVICE OPERATION

Read

Read operations are initiated by both

and

LOW.

The read operation is terminated by either

returning HIGH. This two line control architecture elimi-
nates bus contention in a system environment. The data
bus will be in a high impedance state when either

is HIGH.

Write

Write operations are initiated when both

and

are

LOW and

is HIGH. The X28C256 supports both a

and

controlled write cycle. That is, the address is

latched by the falling edge of either

, whichever

occurs last. Similarly, the data is latched internally by the
rising edge of either

, whichever occurs first.

A byte write operation, once initiated, will automatically
continue to completion, typically within 5ms.

Page Write Operation

The page write feature of the X28C256 allows the entire
memory to be written in 2.5 seconds. Page write allows
two to sixty-four bytes of data to be consecutively written
to the X28C256 prior to the commencement of the
internal programming cycle. The host can fetch data
from another device within the system during a page
write operation (change the source address), but the
page address (A

through A

) for each subsequent

valid write cycle to the part during this operation must be
the same as the initial page address.

The page write mode can be initiated during any write
operation. Following the initial byte write cycle, the host
can write an additional one to sixty-three bytes in the
same manner as the first byte was written. Each succes-
sive byte load cycle, started by the

HIGH to LOW

transition, must begin within 100

s of the falling edge of

the preceding

. If a subsequent

HIGH to LOW

transition is not detected within 100

s, the internal

automatic programming cycle will commence. There is
no page write window limitation. Effectively the page
write window is infinitely wide, so long as the host
continues to access the device within the byte load cycle
time of 100

DATA

Polling (I/O

)

The X28C256 features

DATA

Polling as a method to

indicate to the host system that the byte write or page
write cycle has completed.

DATA

Polling allows a simple

bit test operation to determine the status of the X28C256,
eliminating additional interrupt inputs or external hard-
ware. During the internal programming cycle, any at-
tempt to read the last byte written will produce the
complement of that data on I/O

(i.e. write data = 0xxx

xxxx, read data = 1xxx xxxx). Once the programming
cycle is complete, I/O

will reflect true data. Note: If the

X28C256 is in the protected state and an illegal write
operation is attempted

DATA

Polling will not operate.

Toggle Bit (I/O

)

The X28C256 also provides another method for deter-
mining when the internal write cycle is complete. During
the internal programming cycle I/O

will toggle from

HIGH to LOW and LOW to HIGH on subsequent
attempts to read the device. When the internal cycle is
complete the toggling will cease and the device will be
accessible for additional read or write operations.

Write Operation Status Bits

The X28C256 provides the user two write operation
status bits. These can be used to optimize a system
write cycle time. The status bits are mapped onto the
I/O bus as shown in Figure 1.

Figure 1. Status Bit Assignment

I/O

RESERVED

TOGGLE BIT

DATA POLLING

3855 FHD F11

X28C256

THE TOGGLE BIT I/O

Figure 4. Toggle Bit Bus Sequence

I/O6

X28C256
READY

VOH

VOL

LAST

WRITE

HIGH Z

* Beginning and ending state of I/O6 will vary.

3855 FHD F14

Figure 5. Toggle Bit Software Flow

3855 FHD F15

The Toggle Bit can eliminate the software housekeeping
chore of saving and fetching the last address and data
written to a device in order to implement

DATA

Polling.

This can be especially helpful in an array comprised of
multiple X28C256 memories that is frequently updated.
The timing diagram in Figure 4 illustrates the sequence
of events on the bus. The software flow diagram in
Figure 5 illustrates a method for polling the Toggle Bit.

LOAD ACCUM

FROM ADDR n

COMPARE

ACCUM WITH

ADDR n

X28C256

READY

COMPARE

OK?

YES

LAST WRITE

X28C256

HARDWARE DATA PROTECTION

The X28C256 provides three hardware features (com-
patible with X28C64) that protect nonvolatile data from
inadvertent writes.

· Noise Protection--A

pulse typically less than

20ns will not initiate a write cycle.

· Default V

Sense--All write functions are inhibited

when V

3.5V typically.

· Write Inhibit--Holding either

LOW,

HIGH,

HIGH will prevent an inadvertent write cycle

during power-up and power-down, maintaining data
integrity.

SOFTWARE DATA PROTECTION

The X28C256 offers a software controlled data protec-
tion feature. The X28C256 is shipped from Xicor with the
software data protection NOT ENABLED; that is, the
device will be in the standard operating mode. In this
mode data should be protected during power-up/-down
operations through the use of external circuits. The host
would then have open read and write access of the
device once V

was stable.

The X28C256 can be automatically protected during
power-up and power-down without the need for external
circuits by employing the software data protection fea-
ture. The internal software data protection circuit is
enabled after the first write operation utilizing the soft-
ware algorithm. This circuit is nonvolatile and will remain
set for the life of the device unless the reset command
is issued.

Once the software protection is enabled, the X28C256
is also protected from inadvertent and accidental writes
in the powered-up state. That is, the software algorithm
must be issued prior to writing additional data to the
device.

Software Algorithm

Selecting the software data protection mode requires
the host system to precede data write operations by a
series of three write operations to three specific ad-
dresses. Refer to Figure 6 and 7 for the sequence. The
three-byte sequence opens the page write window
enabling the host to write from one to sixty-four bytes of
data.* Once the page load cycle has been completed,
the device will automatically be returned to the data
protected state.

*Note: Once the three-byte sequence is issued it

must be followed by a valid byte or page write
operation.

X28C256

SOFTWARE DATA PROTECTION
Figure 6. Timing Sequence--Byte or Page Write

3855 FHD F16

Figure 7. Write Sequence for
Software Data Protection

WRITE LAST

BYTE TO

LAST ADDRESS

WRITE DATA 55

TO ADDRESS

2AAA

WRITE DATA A0

TO ADDRESS

5555

WRITE DATA XX

TO ANY

ADDRESS

AFTER tWC

RE-ENTERS DATA

PROTECTED STATE

WRITE DATA AA

TO ADDRESS

5555

BYTE/PAGE
LOAD ENABLED

3855 FHD F17

Regardless of whether the device has previously been
protected or not, once the software data protection
algorithm is used and data has been written, the X28C256
will automatically disable further writes unless another
command is issued to cancel it. If no further commands
are issued the X28C256 will be write protected during
power-down and after any subsequent power-up.

Note: Once initiated, the sequence of write operations

should not be interrupted.

(VCC)

WRITE
PROTECTED

VCC

DATA

ADDR.

5555

2AAA

5555

tBLC MAX

WRITES

BYTE

PAGE

tWC

tBLC MAX

tWPH2

X28C256

RESETTING SOFTWARE DATA PROTECTION
Figure 8. Reset Software Data Protection Timing Sequence

3855 FHD F18

Figure 9. Software Sequence to
Deactivate Software Data Protection

WRITE DATA 55

TO ADDRESS

2AAA

WRITE DATA 55

TO ADDRESS

2AAA

WRITE DATA 80

TO ADDRESS

5555

WRITE DATA AA

TO ADDRESS

5555

WRITE DATA 20

TO ADDRESS

5555

WRITE DATA AA

TO ADDRESS

5555

3855 FHD F19

In the event the user wants to deactivate the software
data protection feature for testing or reprogramming in
an E

PROM programmer, the following six step algo-

rithm will reset the internal protection circuit. After t

the X28C256 will be in standard operating mode.

Note:

Once initiated, the sequence of write operations
should not be interrupted.

STANDARD
OPERATING
MODE

VCC

DATA

ADDR.

5555

2AAA

5555

tWC

5555

2AAA

5555

X28C256

SYSTEM CONSIDERATIONS

Because the X28C256 is frequently used in large memory
arrays it is provided with a two line control architecture
for both read and write operations. Proper usage can
provide the lowest possible power dissipation and elimi-
nate the possibility of contention where multiple I/O pins
share the same bus.

To gain the most benefit it is recommended that

decoded from the address bus and be used as the
primary device selection input. Both

and

would

then be common among all devices in the array. For a
read operation this assures that all deselected devices
are in their standby mode and that only the selected
device(s) is outputting data on the bus.

Because the X28C256 has two power modes, standby
and active, proper decoupling of the memory array is of

prime concern. Enabling

will cause transient current

spikes. The magnitude of these spikes is dependent on
the output capacitive loading of the I/Os. Therefore, the
larger the array sharing a common bus, the larger the
transient spikes. The voltage peaks associated with the
current transients can be suppressed by the proper
selection and placement of decoupling capacitors. As a
minimum, it is recommended that a 0.1

F high fre-

quency ceramic capacitor be used between V

and

at each device. Depending on the size of the array,

the value of the capacitor may have to be larger.

In addition, it is recommended that a 4.7

F electrolytic

bulk capacitor be placed between V

and V

for each

eight devices employed in the array. This bulk capacitor
is employed to overcome the voltage droop caused by
the inductive effects of the PC board traces.

Normalized Active Supply Current
vs. Ambient Temperature

Normalized Standby Supply Current
vs. Ambient Temperature

+25

+125

0.6

0.8

1.0

1.2

1.4

VCC = 5V

AMBIENT TEMPERATURE (

NORMALIZED I

+25

+125

0.6

0.8

1.0

1.2

1.4

VCC = 5V

AMBIENT TEMPERATURE (

NORMALIZED I

SB1

3855 FHD F20.1

3855 FHD F21.1

X28C256

ABSOLUTE MAXIMUM RATINGS*
Temperature under Bias

X28C256 ...................................... 10

C to +85

X28C256I, X28C256M ............... 65

C to +135

Storage Temperature ....................... 65

C to +150

Voltage on any Pin with

Respect to V

SS .......................................

1V to +7V

D.C. Output Current ............................................. 5mA
Lead Temperature

(Soldering, 10 seconds) .............................. 300

*COMMENT
Stresses above those listed under "Absolute Maximum
Ratings" may cause permanent damage to the device.
This is a stress rating only and the functional operation of
the device at these or any other conditions above those
indicated in the operational sections of this specification is
not implied. Exposure to absolute maximum rating condi-
tions for extended periods may affect device reliability.

RECOMMENDED OPERATING CONDITIONS

Temperature

Min.

Max.

Commercial

+70

Industrial

+85

Military

+125

3855 PGM T02.1

Supply Voltage

Limits

X28C256

10%

3855 PGM T03.1

Notes: (1) Typical values are for T

= 25

C and nominal supply voltage and are not tested

(2) I

SB2

max. of 200

A available from Xicor. Contact local sales office and reference X28C256 C7125.

(3) V

min. and V

max. are for reference only and are not tested.

D.C. OPERATING CHARACTERISTICS (over recommended operating conditions, unless otherwise specified)

Limits

Symbol

Parameter

Min.

Typ.

(1)

Max.

Units

Test Conditions

Current (Active)

= V

(TTL Inputs)

All I/O's = Open, Address
Inputs = .4V/2.4V @ f = 5MHz

SB1

Current (Standby)

= V

(TTL Inputs)

All I/O's = Open, Other Inputs = V

SB2

(2)

Current (Standby)

200

500

= V

0.3V,

= V

(CMOS Inputs)

All I/O's = Open,
Other Inputs = V

0.3V

Input Leakage Current

= V

to V

Output Leakage Current

OUT

= V

to V

= V

(3)

Input LOW Voltage

0.8

(3)

Input HIGH Voltage

+ 1

Output LOW Voltage

0.4

= 2.1mA

Output HIGH Voltage

2.4

= 400

3855 PGM T04.2

X28C256

ENDURANCE AND DATA RETENTION

Parameter

Min.

Units

Endurance

100,000

Cycles

Data Retention

100

Years

3855 PGM T05.3

POWER-UP TIMING

Symbol

Parameter

Max.

Units

PUR

(4)

Power-up to Read Operation

100

PUW

(4)

Power-up to Write Operation

3855 PGM T06

CAPACITANCE T

= +25

C, f = 1MHz, V

= 5V

Symbol

Parameter

Max.

Units

Test Conditions

I/O

(4)

Input/Output Capacitance

I/O

= 0V

(4)

Input Capacitance

= 0V

3855 PGM T07.1

A.C. CONDITIONS OF TEST

Input Pulse Levels

0V to 3V

Input Rise and
Fall Times

10ns

Input and Output
Timing Levels

1.5V

3855 PGM T08.1

MODE SELECTION

Mode

I/O

Power

Read

OUT

Active

Write

Active

Standby and

High Z

Standby

Write Inhibit

3855 PGM T09

Note: (4) This parameter is periodically sampled and not 100% tested.

EQUIVALENT A.C. LOAD CIRCUIT

WAVEFORM

INPUTS

OUTPUTS

Must be
steady

Will be
steady

May change
from LOW
to HIGH

Will change
from LOW
to HIGH

May change
from HIGH
to LOW

Will change
from HIGH
to LOW

Don't Care:
Changes
Allowed

Changing:
State Not
Known

N/A

Center Line
is High
Impedance

SYMBOL TABLE

3855 FHD F22.3

1.92K

100pF

OUTPUT

1.37K

X28C256

A.C. CHARACTERISTICS (over recommended operating conditions, unless otherwise specified)

Read Cycle Limits

X28C256-15

X28C256-20

X28C256-25

X28C256

Symbol

Parameter

Min.

Max.

Min.

Max.

Min.

Max.

Min.

Max.

Units

Read Cycle Time

150

200

250

300

Chip Enable Access Time

150

200

250

300

Address Access Time

150

200

250

300

Output Enable Access Time

100

(5)

LOW to Active Output

OLZ

(5)

LOW to Active Output

(5)

HIGH to High Z Output

OHZ

(5)

HIGH to High Z Output

Output Hold from

Address Change

3855 PGM T10.1

Read Cycle

3855 FHD F05

Note: (5) t

min., t

, t

OLZ

min., and t

OHZ

are peridocally sampled and not 100% tested. t

and t

OHZ

are measured, with C

= 5pF, from

the point when

return HIGH (whichever occurs first) to the time when the outputs are no longer driven.

tCE

tRC

ADDRESS

DATA VALID

tOE

tLZ

tOLZ

tOH

tAA

tHZ

tOHZ

DATA I/O

VIH

HIGH Z

X28C256

WRITE CYCLE LIMITS

Symbol

Parameter

Min.

(9)

Typ.

(6)

Max.

Units

(7)

Write Cycle Time

Address Setup Time

Address Hold Time

150

Write Setup Time

Write Hold Time

Pulse Width

100

OES

HIGH Setup Time

OEH

HIGH Hold Time

Pulse Width

100

WPH

HIGH Recovery

WPH2

(8)

SDP

Recovery

Data Valid

Data Setup

Data Hold

Delay to Next Write

BLC

(9)

Byte Load Cycle

100

3855 PGM T11.1

Controlled Write Cycle

3855 FHD F06

Notes: (6) Typical values are for T

= 25

C and nominal supply voltage.

(7) t

is the minimum cycle time to be allowed from the system perspective unless polling techniques are used. It is the maximum

time the device requires to automatically complete the internal write operation.

(8) t

WPH

is the normal page write operation

recovery time. t

WPH2

is the

recovery time needed only after the end of issuing

the three-byte SDP command sequence and before writing the first byte of data to the array. Refer to Figure 6 which illustrates
the t

WPH2

requirement.

(9) For faster t

and t

BLC

, refer to X28HC256 or X28VC256.

ADDRESS

tAS

tWC

tAH

tOES

tDV

tDS

tDH

tOEH

DATA IN

DATA OUT

HIGH Z

DATA VALID

tCS

tCH

tWP

X28C256

Controlled Write Cycle

Notes: (10) Between successive byte writes within a page write operation,

can be strobed LOW: e.g. this can be done with

and

HIGH to fetch data from another memory device within the system for the next write; or with

HIGH and

LOW effectively

performing a polling operation.

(11) The timings shown above are unique to page write operations. Individual byte load operations within the page write must

conform to either the

controlled write cycle timing.

3855 FHD F07

Page Write Cycle

3855 FHD F08

ADDRESS

tAS

tOEH

tWC

tAH

tOES

tCS

tDV

tDS

tDH

tCH

DATA IN

DATA OUT

HIGH Z

DATA VALID

tCW

(10)

LAST BYTE

BYTE 0

BYTE 1

BYTE 2

BYTE n

BYTE n+1

BYTE n+2

tWP

tWPH

tBLC

tWC

ADDRESS*

(11)

I/O

*For each successive write within the page write operation, A6A14 should be the same or

writes to an unknown address could occur.

X28C256

PACKAGING INFORMATION

0.021 (0.53)

0.013 (0.33)

0.420 (10.67)

0.050 (1.27) TYP.

TYP. 0.017 (0.43)

0.045 (1.14) x 45

0.300 (7.62)

REF.

0.453 (11.51)

0.447 (11.35)

TYP. 0.450 (11.43)

0.495 (12.57)

0.485 (12.32)

TYP. 0.490 (12.45)

PIN 1

0.400

(10.16)

REF.

0.553 (14.05)

0.547 (13.89)

TYP. 0.550 (13.97)

0.595 (15.11)

0.585 (14.86)

TYP. 0.590 (14.99)

TYP.

0.048 (1.22)

0.042 (1.07)

0.140 (3.56)

0.100 (2.45)

TYP. 0.136 (3.45)

0.095 (2.41)

0.060 (1.52)

0.015 (0.38)

SEATING PLANE

0.004 LEAD

CO PLANARITY

3926 FHD F13

32-LEAD PLASTIC LEADED CHIP CARRIER PACKAGE TYPE J

NOTES:
1. ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
2. DIMENSIONS WITH NO TOLERANCE FOR REFERENCE ONLY

0.510"

TYPICAL

0.050"

TYPICAL

0.050"

TYPICAL

0.300"

REF

FOOTPRINT

0.400"

0.410"

0.030" TYPICAL

32 PLACES

X28C256

PACKAGING INFORMATION

0.150 (3.81) BSC

0.458 (11.63)

0.442 (11.22)

PIN 1

3926 FHD F14

0.020 (0.51) x 45

REF.

0.095 (2.41)

0.075 (1.91)

0.022 (0.56)

0.006 (0.15)

0.055 (1.39)

0.045 (1.14)

TYP. (4) PLCS.

0.040 (1.02) x 45

REF.

TYP. (3) PLCS.

0.050 (1.27) BSC

0.028 (0.71)

0.022 (0.56)

(32) PLCS.

0.200 (5.08)

BSC

0.558 (14.17)

0.088 (2.24)

0.050 (1.27)

0.120 (3.05)

0.060 (1.52)

PIN 1 INDEX CORNER

32-PAD CERAMIC LEADLESS CHIP CARRIER PACKAGE TYPE E

NOTE:
1. ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
2. TOLERANCE:

1% NLT

0.005 (0.127)

0.300 (7.62)

BSC

0.015 (0.38)

MIN.

0.400 (10.16)

BSC

0.560 (14.22)

0.540 (13.71)

DIA.

0.015 (0.38)

0.003 (0.08)

X28C256

PACKAGING INFORMATION

3926 ILL F38.1

8.02 (0.315)

7.98 (0.314)

1.18 (0.046)
1.02 (0.040)

0.17 (0.007)
0.03 (0.001)

0.26 (0.010)

0.14 (0.006)

0.50 (0.0197) BSC

0.58 (0.023)
0.42 (0.017)

14.15 (0.557)
13.83 (0.544)

12.50 (0.492)

12.30 (0.484)

PIN #1 IDENT.
O 0.76 (0.03)

SEATING
PLANE

SEE NOTE 2

0.50 ± 0.04

(0.0197 ± 0.0016)

0.30 ± 0.05

(0.012 ± 0.002)

14.80 ± 0.05

(0.583 ± 0.002)

1.30 ± 0.05

(0.051 ± 0.002)

0.17 (0.007)
0.03 (0.001)

TYPICAL

32 PLACES

15 EQ. SPC. 0.50 ± 0.04

0.0197 ± 0.016 = 7.50 ± 0.06

(0.295 ± 0.0024) OVERALL

TOL. NON-CUMULATIVE

SOLDER PADS

FOOTPRINT

NOTE:
1. ALL DIMENSIONS ARE SHOWN IN MILLIMETERS (INCHES IN PARENTHESES).

32-LEAD THIN SMALL OUTLINE PACKAGE (TSOP) TYPE T

X28C256

Device

ORDERING INFORMATION

Access Time
15 = 150ns
20 = 200ns
25 = 250ns
Blank = 300ns
35 = 350ns

Temperature Range
Blank = Commercial = 0

C to +70

I = Industrial = 40

C to +85

M = Military = 55

C to +125

MB = MIL-STD-883

Package
P = 28-Lead Plastic DIP
D = 28-Lead Cerdip
J = 32-Lead PLCC
E = 32-Pad LCC
F = 28-Lead Flat Pack
K = 28-Lead Pin Grid Array
S = 28-Lead Plastic SOIC
T = 32-Lead TSOP

X28C256 X X

-X

LIMITED WARRANTY

Devices sold by Xicor, Inc. are covered by the warranty and patent indemnification provisions appearing in its Terms of Sale only. Xicor, Inc. makes no warranty,
express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement.
Xicor, Inc. makes no warranty of merchantability or fitness for any purpose. Xicor, Inc. reserves the right to discontinue production and change specifications and
prices at any time and without notice.

Xicor, Inc. assumes no responsibility for the use of any circuitry other than circuitry embodied in a Xicor, Inc. product. No other circuits, patents, licenses are
implied.

U.S. PATENTS
Xicor products are covered by one or more of the following U.S. Patents: 4,263,664; 4,274,012; 4,300,212; 4,314,265; 4,326,134; 4,393,481; 4,404,475;
4,450,402; 4,486,769; 4,488,060; 4,520,461; 4,533,846; 4,599,706; 4,617,652; 4,668,932; 4,752,912; 4,829, 482; 4,874, 967; 4,883, 976. Foreign patents and
additional patents pending.

LIFE RELATED POLICY
In situations where semiconductor component failure may endanger life, system designers using this product should design the system with appropriate error
detection and correction, redundancy and back-up features to prevent such an occurence.

Xicor's products are not authorized for use in critical components in life support devices or systems.
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose

failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant
injury to the user.

2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life

support device or system, or to affect its safety or effectiveness.

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: X28C256-15

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: X28C256-15